Calculations of Absolute Free Energies, Enthalpies, and Entropies for Drug Binding

Computer simulation methods can aid in the rational design of drugs aimed at a specific target, typically a protein. The affinity of a drug for its target is given by the free energy of binding. Binding can be further characterized by the enthalpy and entropy changes in the process. Methods exist to determine exact free energies, enthalpies, and entropies that are dependent only on the quality of the potential model and adequate sampling of conformational degrees of freedom. Entropy and enthalpy are roughly an order of magnitude more difficult to calculate than the free energy. This project combines a replica exchange method for enhanced sampling, designed to be efficient for protein-sized systems, with free energy calculations. This approach, replica exchange with dynamical scaling (REDS), uses two conventional simulations at different temperatures so that the entropy can be found from the temperature dependence of the free energy. A third replica is placed between them, with a modified Hamiltonian that allows it to span the temperature range of the conventional replicas. REDS provides temperature-dependent data and aids in sampling. It is applied to the bromodomain-containing protein 4 (BRD4) system. We find that for the force fields used, the free energies are accurate but the entropies and enthalpies are not, with the entropic contribution being too positive. Reproducing the entropy and enthalpy of binding appears to be a more stringent test of the force fields than reproducing the free energy.

Let's Move with Leon-A qualitative evaluation of a UK digital intervention to improve physical activity in people with a musculoskeletal condition

OBJECTIVE

This article presents a qualitative evaluation of a 13-week digital intervention, 'Let's Move with Leon', designed to improve physical activity in people with a musculoskeletal condition.

STUDY DESIGN

A qualitative evaluation embedded within a randomised controlled trial assessing the effectiveness of the intervention at improving self-reported physical activity.

METHODS

A total of 184 participants received the intervention and were asked each week for 13 weeks to provide comment on their use and the usefulness of the digital physical activity behaviour change intervention. In addition, after 13 weeks, 12 participants took part in a semistructured interview to understand their use and the usefulness of the intervention. A thematic analysis was conducted on the combined qualitative data set.

RESULTS

A total of 128 of the 184 intervention participants (70.11%) provided at least one qualitative comment over the course of the evaluation (mean number of comments per participant = 5); in total, 674 comments were received. The thematic analysis identified three themes: (1) dipping in and out, (2) one size does not fit all and (3) monitoring and feedback. The qualitative data suggest that participants used the intervention sporadically, dipping in and out due to other commitments, and competing programmes, their changing physical ability, confidence and motivation. Not getting off to a good start was detrimental to use; many wanted to come back to the programme at a more appropriate time. A 'one size fits' approach catered for some but not all participants. Whilst not a predetermined intervention component the act of monitoring levels of activity as a data collection method seemed to encourage physical activity but may also result in negative social comparisons.

CONCLUSION

Digital physical activity behaviour change interventions are not one-size-fits-all; personalisation is key. Monitoring of activity by a named person can create commitment. Many dip in and out. Digital physical activity behaviour change interventions could complement physiotherapy exercises for people with musculoskeletal conditions. Signposting to local activities should be considered.

A Multifunctional Dehalobacter? Tandem Chloroform and Dichloromethane Degradation in a Mixed Microbial Culture

Chloroform (CF) and dichloromethane (DCM) contaminate groundwater sites around the world but can be cleaned up through bioremediation. Although several strains of Dehalobacter restrictus can reduce CF to DCM and multiple Peptococcaceae can ferment DCM, these processes cannot typically happen simultaneously due to CF sensitivity in the known DCM-degraders or electron donor competition. Here, we present a mixed microbial culture that can simultaneously metabolize CF and DCM and create an additional enrichment culture fed only DCM. Through genus-specific quantitative polymerase chain reaction, we find that Dehalobacter grows while either CF alone or DCM alone is converted, indicating its involvement in both metabolic steps. Additionally, the culture was maintained for over 1400 days without the addition of an exogenous electron donor, and through electron balance calculations, we show that DCM metabolism would produce sufficient reducing equivalents (likely hydrogen) for CF respiration. Together, these results suggest intraspecies electron transfer could occur to continually reduce CF in the culture. Minimizing the addition of electron donor reduces the cost of bioremediation, and "self-feeding" could prolong bioremediation activity long after donor addition ends. Overall, understanding this mechanism informs strategies for culture maintenance and scale-up and benefits contaminated sites where the culture is employed for remediation worldwide.

Modifications to therapeutic plasma exchange to achieve rapid exchange on cardiopulmonary bypass prior to pediatric cardiac transplant

BACKGROUND

Cardiac transplants increasingly occur following placement of ventricular assist devices (VADs). A strong association exists between human leukocyte antigen (HLA) sensitization and VAD placement; however, desensitization protocols that utilize therapeutic plasma exchange (TPE) are fraught with technical challenges and are at increased risk of adverse events. In response to increased VAD utilization in our pre-transplant population, we developed a new institutional standard for TPE in the operating room.

METHODS

Through a multidisciplinary effort, we developed an institutional protocol for intraoperative TPE immediately prior to cardiac transplantation after cannulation onto cardiopulmonary bypass (CPB). All procedures used the standard TPE protocol on the Terumo Optia (Terumo BCT, Lakewood, CO, USA), but incorporated multiple modifications to limit patients' bypass times, and to coordinate with the surgical teams. These modifications included deliberate misidentification of replacement fluid and maximization of the citrate infusion rate.

RESULTS

These adjustments allowed the machine to run at maximal inlet speeds, minimizing duration of TPE. To date, 11 patients have been treated with this protocol. All survived their cardiac transplantation operation. Hypocalcemia and hypotension were noted; however, none of these adverse events appeared to have clinical impact. Technical complications included unexpected fibrin deposition in the TPE circuit and air in the inlet line due to surgical manipulation of the CPB cannula. No thromboembolic complications occurred in any patient.

CONCLUSION

We feel that this procedure can be rapidly and safely performed in HLA sensitized pediatric patients on CPB to limit the risk of antibody mediated rejection of their heart transplant.

Development of a Digital Twin for the Prediction and Control of Supersaturation during Batch Cooling Crystallization

Fine chemicals produced via batch crystallization with properties dependent on the crystal size distribution require precise control of supersaturation, which drives the evolution of crystal size over time. Model predictive control (MPC) of supersaturation using a mechanistic model to represent the behavior of a crystallization process requires less experimental time and resources compared with fully empirical model-based control methods. Experimental characterization of the hexamine-ethanol crystallization system was performed in order to collect the parameters required to build a one-dimensional (1D) population balance model (PBM) in gPROMS FormulatedProducts software (Siemens-PSE Ltd.). Analysis of the metastable zone width (MSZW) and a series of seeded batch cooling crystallizations informed the suitable process conditions selected for supersaturation control experiments. The gPROMS model was integrated with the control software PharmaMV (Perceptive Engineering Ltd.) to create a digital twin of the crystallizer. Simulated batch crystallizations were used to train two statistical MPC blocks, allowing for in silico supersaturation control simulations to develop an effective control strategy. In the supersaturation set-point range of 0.012-0.036, the digital twin displayed excellent performance that would require minimal controller tuning to steady out any instabilities. The MPC strategy was implemented on a physical 500 mL crystallizer, with the simulated solution concentration replaced by in situ measurements from calibrated attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Physical supersaturation control performance was slightly more unstable than the in silico tests, which is consistent with expected disturbances to the heat transfer, which were not specifically modeled in simulations. Overall, the level of supersaturation control in a real crystallizer was found to be accurate and precise enough to consider future adaptations to the MPC strategy for more advanced control objectives, such as the crystal size.

Cerebral revascularization surgery reduces cerebrovascular events in children with sickle cell disease and moyamoya syndrome: Results of the stroke in sickle cell revascularization surgery retrospective study

BACKGROUND

Recent studies suggest that cerebral revascularization surgery may be a safe and effective therapy to reduce stroke risk in patients with sickle cell disease and moyamoya syndrome (SCD-MMS).

METHODS

We performed a multicenter, retrospective study of children with SCD-MMS treated with conservative management alone (conservative group)-chronic blood transfusion and/or hydroxyurea-versus conservative management plus surgical revascularization (surgery group). We monitored cerebrovascular event (CVE) rates-a composite of strokes and transient ischemic attacks. Multivariable logistic regression was used to compare CVE occurrence and multivariable Poisson regression was used to compare incidence rates between groups. Covariates in multivariable models included age at treatment start, age at moyamoya diagnosis, antiplatelet use, CVE history, and the risk period length.

RESULTS

We identified 141 patients with SCD-MMS, 78 (55.3%) in the surgery group and 63 (44.7%) in the conservative group. Compared with the conservative group, preoperatively the surgery group had a younger age at moyamoya diagnosis, worse baseline modified Rankin scale scores, and increased prevalence of CVEs. Despite more severe pretreatment disease, the surgery group had reduced odds of new CVEs after surgery (odds ratio = 0.27, 95% confidence interval [CI] = 0.08-0.94, p = .040). Furthermore, comparing surgery group patients during presurgical versus postsurgical periods, CVEs odds were significantly reduced after surgery (odds ratio = 0.22, 95% CI = 0.08-0.58, p = .002).

CONCLUSIONS

When added to conservative management, cerebral revascularization surgery appears to reduce the risk of CVEs in patients with SCD-MMS. A prospective study will be needed to validate these findings.

A199 BIOFILMS IN THE APPENDIX AND OTHER NON-INFLAMED SECTIONS OF THE COLON IN PEDIATRIC PATIENTS WITH INFLAMMATORY BOWEL DISEASES

Background

Biofilms, aggregated bacteria colonizing the extracellular polymeric substances matrix, are associated with the mucosa of inflammatory bowel diseases (IBD) patients with some studies showing a mean density of the mucosal biofilms 2-fold higher in IBD patients than in controls. The appendix, which is a highly immune organ, seems to be involved in IBD pathogenesis.

Purpose

In this study we aimed to evaluate biofilms in the appendix and other non-inflamed regions of the colon in pediatric IBD patients. We hypothesized that biofilms composed of pathobionts in these sections could drive inflammation in IBD patients.

Method

Tissues from the appendix, peri-appendicular region, cecum, and ascending colon (ASC), collected from the resected colons of 9 pediatric IBD patients and one pediatric non-IBD patient, preserved in methanol Carnoy’s solution were processed and paraffin embedded. Combined fluorescence in situ hybridization (FISH) for biofilms (probe: EUB338) and immunofluorescence (IF) mucin staining (MUC2) identified biofilms and their location. Biofilm formation capacity of culturable bacteria (identified through 16S DNA Sanger sequencing) from these sections was measured. Interleukin (IL)-8 (pro-inflammatory chemokine) and IL-10 (anti-inflammatory cytokine) expressions were assessed by tissue qPCR.

Result(s)

FISH demonstrated biofilms in these sections, in close proximity to epithelial cells. We used a biofilm formation assay to assess the ability of the identified bacteria from these sections to form biofilms, illustrating their potential to colonize and evade host defense and potential antibiotics. We found that Enterococcus avium has a significantly higher ability to form biofilms than the negative control. IL-8 and IL-10 both had the highest expression level in the appendix and peri-appendicular region and the lowest in the ASC among all the patients, suggesting an active immune response. Mechanistic experiments are in progress to investigate the type of bacteria involved in the biofilms and their effects on the gut barrier integrity.

Conclusion(s)

Biofilms adjacent to the epithelium, especially in the appendix and peri-appendix, could interact with or invade epithelial cells. The elevated chemokine transcript level in the appendix could reflect the recruitment of immune cells to this section following bacterial invasion, resulting in the activation of the immune system. Identifying the bacteria involved in the biofilms and clarifying their characteristics will aid us in developing novel microbe-altering treatment strategies or personalized medicine.

Disclosure of Interest

None Declared

Clinical outcomes of children and adolescents with sickle cell disease and COVID-19 infection: A year in review at a metropolitan tertiary pediatric hospital

Background

COVID-19 was declared a global pandemic in March 2020. Early reports were primarily in adults, and sickle cell disease (SCD) was classified as a risk factor for severe COVID-19 disease. However, there are a limited number of primarily multi-center studies reporting on the clinical course of pediatric patients with SCD and COVID-19.

Methods

We conducted an observational study of all patients with SCD diagnosed with COVID-19 at our institution between March 31, 2020, and February 12, 2021. Demographic and clinical characteristics of this group were collected by retrospective chart review.

Results

A total of 55 patients were studied, including 38 children and 17 adolescents. Demographics, acute COVID-19 clinical presentation, respiratory support, laboratory findings, healthcare utilization, and SCD modifying therapies were comparable between the children and adolescents. Seventy-three percent (N = 40) of all patients required emergency department care or hospitalization. While 47% (N = 26) were hospitalized, only 5% (N = 3) of all patients required intensive care unit admission. Patients frequently had concurrent vaso-occlusive pain crisis (VOC) (N = 17, 43%) and acute chest syndrome (ACS) (N = 14, 35%). Those with ACS or an oxygen requirement had significantly higher white blood cell count, lower nadir hemoglobin, and higher D-dimers, supporting a pro-inflammatory and coagulopathic picture. Non-hospitalized patients were more likely to be on hydroxyurea than hospitalized patients (79 vs. 50%, p = 0.023).

Conclusion

Children and adolescent patients with SCD and acute COVID-19 often present with ACS and VOC pain requiring hospital-level care. Hydroxyurea treatment appears to be protective. We observed no mortality despite variable morbidity.

Investigation of Active Site Amino Acid Influence on Carbon and Chlorine Isotope Fractionation during Reductive Dechlorination

Reductive dehalogenases (RDases) are corrinoid-dependent enzymes that reductively dehalogenate organohalides in respiratory processes. By comparing isotope effects in biotically-catalyzed reactions to reference experiments with abiotic corrinoid-catalysts, compound-specific isotope analysis (CSIA) has been shown to yield valuable insights into enzyme mechanisms and kinetics, including RDases. Here, we report isotopic fractionation (ε) during biotransformation of chloroform (CF) for carbon (εC = -1.52 ± 0.34‰) and chlorine (εCl = -1.84 ± 0.19‰), corresponding to a ΛC/Cl value of 1.13 ± 0.35. These results are highly suppressed compared to isotope effects observed both during CF biotransformation by another organism with a highly similar RDase (> 95% sequence identity) at the amino acid level, and to those observed during abiotic dehalogenation of CF. Amino acid differences occur at four locations within the two different RDases' active sites, and this study examines whether these differences potentially affect the observed εC, εCl, and ΛC/Cl. Structural protein models approximating the locations of the residues elucidate possible controls on reaction mechanisms and/or substrate binding efficiency. These four locations are not conserved among other chloroalkane reducing RDases with high amino acid similarity (> 90%), suggesting that these locations may be important in determining isotope fractionation within this homologous group of RDases.

Are multiple-use bottles of chlorhexidine solutions at risk of contamination in joint replacement surgery?

INTRODUCTION

Chlorhexidine gluconate 2% w/v in isopropanol 70% solutions in multiple-use bottles is commonly used in surgery as a cost-effective method for skin disinfection. However, multiple-use bottles risk contamination. This study aims to test whether bacterial contamination of multiple-use bottles or their solutions occurs once open and on use between different patients.

METHODS

Consecutive samples were taken each time a chlorhexidine bottle was used over a 7-day study period. Samples were tested using blood culture, agar plate and mass spectrometry.

RESULTS

No growth was observed in 52 samples taken from 18 bottles inoculated into blood culture bottles. Four growths on agar plate culture were determined to be contaminants from the sampling process.

CONCLUSIONS

This study supports the use of multiple-use bottled chlorhexidine solutions as safe and cost-effective in surgical practice.

The reach and benefits of a digital intervention to improve physical activity in people with a musculoskeletal condition delivered during the COVID-19 pandemic in the UK

Aim:

To evaluate a digital intervention to improve physical activity in people in the UK with a musculoskeletal condition delivered during movement restrictions brought about because of the COVID-19 pandemic.

Method:

Service evaluation data collected from 26,041 participants over 5 months was assessed against national datasets to understand the reach and representativeness of the digital physical activity intervention. Measures to restrict the movement and interaction of people were in place during these 5 months. Cross-sectional data from 2752 participants across different stages of the 12-week programme assessed levels of physical activity and the components of behaviour as defined by the COM-B model (Capability, Opportunity, Motivation = Behaviour). Regression analysis investigated the relationship between programme stage and physical activity and the components of behaviour.

Results:

In comparison to the UK population of people with a musculoskeletal condition, the intervention participants were over-represented by females, White, and inactive people. A cross-sectional analysis suggested that the number of participants regularly active increased by programme stage. Scores for the behavioural components of automatic and reflective motivation, physical and psychological capability, and physical opportunity were also improved by programme stage.

Conclusion:

The service evaluation suggests that the digital intervention, designed to improve physical activity in people with a musculoskeletal condition, could be beneficial during measures to restrict movement to slow the spread of infectious disease in those who are already motivated to become or stay active.

Preventing antibody positive delayed hemolytic transfusion reactions in sickle cell disease: Lessons learned from a case

INTRODUCTION

Red blood cell (RBC) transfusions are important in the management of patients with sickle cell disease (SCD). However, a potentially catastrophic complication of transfusion in this population is the delayed hemolytic transfusion reaction (DHTR). The pathophysiology of all DHTRs is not understood, but some are known to be caused by an anamnestic resurgence of RBC alloantibodies.

CASE PRESENTATION

A child with SCD transfused for acute chest syndrome re-presented a week after hospital discharge with severe anaemia, hemolysis, and a newly detected anti-E. This patient had been previously transfused years ago at an outside institution and the anti-E had not been previously documented.

DISCUSSION

The presented case of an antibody positive DHTR illustrates several concepts critical to the prevention of this complication. RBC alloantibodies must be detected and this information must be shared. Prophylactic C/c, E/e, K antigen matching is helpful for patients with SCD, but systems must be in place to identify these patients. Patients transfused at multiple different hospitals are especially at risk for this complication and efforts are needed to prevent them from suffering a DHTR.

A237 VIRULENCE POTENTIAL OF BACTERIA ISOLATED FROM NON-INFLAMED COLON IN PATIENTS WITH INFLAMMATORY BOWEL DISEASES

Background

As inflammation can impact microbes, our lab has focused on non-inflamed bowel sections of patients with inflammatory bowel diseases (IBD) and found bacterial alterations in the terminal ileum. We are also interested in the appendix given the involvement of the peri-appendicular region and effects of appendectomy in ulcerative colitis.

Aims

In this study, we aimed to identify and evaluate microbes from the appendix and non-inflamed regions of the colon in IBD patients. We hypothesized that microbes originating from the non-inflamed sections of the colon or appendix are more invasive and could trigger inflammation in IBD patients.

Methods

16S DNA Sanger sequencing was performed on bacteria, aerobically and anaerobically cultured from tissues of the appendix, peri-appendicular region, cecum, and ascending colon, collected from the resected colons of 5 pediatric IBD patients. The invasive capacity of the identified bacteria was evaluated by gentamicin protection assays on Caco-2 intestinal epithelial cells in vitro. Presence of select invasive or adhesive genes in the bacteria was assessed by PCR.

Results

Escherichia coli was the most frequently cultured species in the aerobic cultures; additional aerobic species included Enterococcus and Klebsiella. Bifidobacterium and Erysipelatoclostridium were identified among the anaerobic cultures. Gentamicin protection assays indicated that Klebsiella isolated from the peri-appendicular region was significantly more invasive (mean ~3000 CFU/ml) than HB101 (~1000 CFU/ml; non-invasive control; P<0.05). Enterococcus avium and Enterococcus faecalis were also more invasive than HB101 in the peri-appendicular region (~10000 CFU/ml) and cecum (~4000 CFU/ml; P<0.05), respectively. E. coli isolated from the appendix showed a higher invasive potential (~3000 CFU/ml) than E. coli isolated from other sections. Additionally, PCR showed that E. coli obtained from different sections, except the ascending colon of one the patients, had the fimH gene while the other types of bacteria did not. None of the isolated bacteria had Hemolysin ( hlyA) or attaching and effacing ( eaeA) genes.

Conclusions

Bacteria, especially E. coli, from non-inflamed bowel in IBD (including the appendix) appear to have increased invasive potential. This suggests that the microenvironment in these regions could be altered, resulting in increased invasion of bacteria or the gut harboring more invasive microbial populations in IBD patients. As a result, inflammation could be triggered or exacerbated through this reservoir of pathobionts.

Funding Agencies

CIHR

Online training resources to aid therapeutic radiographers in engaging in conversations about physical activity and diet: A mixed methods study

INTRODUCTION

This study explored changes in therapeutic radiographers' (TRs) self-reported knowledge and skills to engage in conversations about physical activity and diet with people living with and beyond cancer following completion of publicly available online courses.

METHODS

Participants were randomly assigned to two of five online courses that aim to support health professionals to engage in conversations about physical activity and diet in the oncology setting. Participants rated their agreement with 18 statements related to the COM-B (capability, opportunity and motivation-behaviour) model components following completion of an online course on healthy diet (n = 16) and physical activity (n = 21). Semi-structured telephone interviews (n = 21) were also conducted. Analysis of the interviews was guided by the Theoretical Domains Framework.

RESULTS

Overall, the online courses were acceptable and the TRs in this study self-reported improved COM to deliver advice on physical activity and diet. The inclusion of the evidence and scientific rationale on the benefits of diet and physical activity, and also guidance on how to start conversations with patients were highlighted as important features of the courses. Suggestions for adaptations to the nutrition courses included the need for content that accounts for the side effects cancer patients experience while undergoing treatment. To support the implementation of training and the delivery of advice on these topics, multi-disciplinary working, organisational support and guidance around professional role boundaries were highlighted as important.

CONCLUSION

Current publicly available online courses on physical activity and diet for oncology health professionals can reduce some barriers among TRs to providing advice to those living with and beyond cancer.

IMPLICATIONS FOR PRACTICE

Existing online training courses could be used to support TRs to deliver physical activity and dietary advice in practice. Findings show that these courses can be disseminated within radiotherapy departments. The results also highlight a number of important considerations for the implementation of brief health behaviour advice and online training interventions on physical activity and diet within cancer care.

Search for B^{+}→K^{+}νν[over ¯] Decays Using an Inclusive Tagging Method at Belle II

A search for the flavor-changing neutral-current decay B^{+}→K^{+}νν[over ¯] is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63  fb^{-1} collected at the ϒ(4S) resonance and a sample of 9  fb^{-1} collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B^{+}→K^{+}νν[over ¯] decay, but also the inclusive properties of the other B meson in the ϒ(4S)→BB[over ¯] event, to suppress the background from other B meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B^{+}→K^{+}νν[over ¯] of 4.1×10^{-5} is set at the 90% confidence level.

Low Rates of Cerebral Infarction after Hematopoietic Stem Cell Transplantation in Patients with Sickle Cell Disease at High Risk for Stroke

Hematopoietic stem cell transplantation (HSCT) can be curative for sickle cell disease (SCD). SCD patients with cerebrovascular disease are often referred for HSCT. The objective of this study was to describe neurologic outcomes after HSCT in patients with pre-existing SCD and cerebrovascular comorbidity. Patients with SCD treated with HSCT at a single center between 1996 and 2019 were identified. Patients with cerebral ischemia and/or vasculopathy before undergoing HSCT were included. Patients with graft failure were excluded. The cohort was divided into 3 groups: symptomatic stroke, vasculopathy without symptomatic stroke, and isolated silent cerebral infarction (SCI). Magnetic resonance imaging/angiography and neurologic assessments pre- and post-HSCT were analyzed to assess outcomes. In a cohort of 44 patients, there were 25 with symptomatic infarction, 10 with vasculopathy, and 9 with isolated SCI. Post-HSCT ischemic injury (2 symptomatic strokes, 2 SCIs) was identified in 4 patients, all with previous symptomatic infarction. Within this group (n = 25), the post-HSCT incidence of subsequent symptomatic infarction was 1.6 events/100 patient-years, and SCIs occurred at a rate of 2.2 events/100 patient-years. No patient had progression of vasculopathy post-HSCT. Our data show a low incidence of new ischemic injury after successful HSCT for SCD. Patients with a history of both symptomatic stroke and vasculopathy are at greatest risk for post-HSCT ischemic injury.

Quality of life after transcatheter aortic valve implantation: Perspectives from a Canadian data base

Funding Acknowledgements

Type of funding sources: None.

Background

We examined changes in quality of life (QOL) of patients after transcatheter aortic valve implantation (TAVI). 

Methods

We conducted an observational cohort study of consecutive patients who had TAVI between 2016-2019 in British Columbia, Canada. QOL was measured at baseline, 30-day and 1-year using the Kansas City Cardiomyopathy Questionnaire (KCCQ-OS). We used linear regression modelling to examine factors associated with 30-day changes in QOL, logistic regression modelling to identify predictors of having a poor outcome, and Cox regression modelling to ascertain risk estimates of the effect of QOL on 1-year mortality. 

Results

The cohort included 1,706 patients [742 women (43.5%)]; median [interquartile range, IQR] age 83 (77,86). Median (IQR) baseline KCCQ-OS was 45 (28.2,67), indicating severe impairment. Patients alive at 1-year (91.3%) reported a mean improvement of 24.1 (95% CI, 22.7-25.6) points in the KCCQ-OS at 30-day, which was sustained at 1-year (25.3; 95% CI, 23.8,26.8). Older age, lower baseline health status, lower aortic valve gradient, lower hemoglobin, atrial fibrillation and non-transfemoral access were associated with worse 30-day QOL. At 1-year, 65% of patients had a favourable outcome; additional risk factors for 1-year mortality (8.7%) were male sex, NYHA Class IV, severe pulmonary and renal disease, diabetes, and in-patient status.  

Conclusions

TAVI is associated with significant early improvement in QOL which is sustained at 1 year in a "real world" registry.  The inclusion of QOL can support treatment decision and the patient-centred evaluation of TAVI

Impact of universal irradiation on chronic transfusion for sickle cell disease

BACKGROUND

Irradiation of blood products prevents transfusion-associated graft-versus-host disease, but most patients do not require this modification which could have an adverse impact on transfusion outcomes. We hypothesized that irradiation may increase transfusion requirements for patients with sickle cell disease (SCD) receiving chronic transfusion.

STUDY DESIGN AND METHODS

Our pediatric hospital implemented a new policy of universal blood product irradiation in May 2018. We conducted a retrospective chart review of patients with SCD receiving chronic red blood cell (RBC) transfusion throughout the year before and after institution of this policy. The primary outcome was the change in RBC transfusion volume per patient weight transfused during the pre- vs. post- universal irradiation period. Secondary outcomes were the change in median pretransfusion laboratory values.

RESULTS

Among 17 patients, 8 (47%) received more RBCs the year before irradiation and 9 (53%) received more the year after irradiation. Implementation of universal irradiation did not significantly increase transfusion volumes needed to clinically manage this population (median change +1.7 ml/kg/year, p = .54). Additionally, there were no significant changes in absolute reticulocyte count, hemoglobin, hemoglobin S%, white blood cell count, lactate dehydrogenase, total bilirubin, serum potassium, and ferritin during the two time periods.

CONCLUSION

In a cohort of patients with SCD receiving simple chronic transfusion, irradiation did not impact transfusion requirements or pertinent pretransfusion laboratory values. Irradiation does not appear to have clinically significant consequences for SCD chronic transfusion management.

Anaerobic Benzene Biodegradation Linked to the Growth of Highly Specific Bacterial Clades

Reliance on bioremediation to remove benzene from anoxic environments has proven risky for decades but for unknown reasons. Research has revealed a strong link between anaerobic benzene biodegradation and the enrichment of highly specific microbes, including Thermincola in the family Peptococcaceae and the deltaproteobacterial Candidate Sva0485 clade. Using aquifer materials from Canadian Forces Base Borden, we compared five bioremediation approaches in batch microcosms. Under conditions simulating natural attenuation or sulfate biostimulation, benzene was not degraded after 1-2 years of incubation and no enrichment of known benzene-degrading microbes occurred. In contrast, nitrate-amended microcosms reported benzene biodegradation coincident with significant growth of Thermincola spp., along with a functional gene presumed to catalyze anaerobic benzene carboxylation (abcA). Inoculation with 2.5% of a methanogenic benzene-degrading consortium containing Sva0485 (Deltaproteobacteria ORM2) resulted in benzene biodegradation in the presence of sulfate or under methanogenic conditions. The presence of other hydrocarbon co-contaminants decreased the rates of benzene degradation by a factor of 2 to 4. Tracking the abundance of the abcA gene and 16S rRNA genes specific for benzene-degrading Thermincola and Sva0485 is recommended to monitor benzene bioremediation in anoxic groundwater systems to further uncover growth-rate-limiting conditions for these two intriguing phylotypes.

Screening for new red blood cell alloantibodies after transfusion in patients with sickle cell disease

BACKGROUND

Patients with sickle cell disease (SCD) are frequent recipients of red blood cell (RBC) transfusions and are at risk for RBC alloimmunization. RBC alloimmunization is diagnosed by identifying RBC alloantibodies as part of pre-transfusion testing, but this testing fails to detect alloantibodies that have evanesced. It may be beneficial to screen for new RBC alloantibody development after transfusion before possible antibody evanescence.

STUDY DESIGN AND METHODS

Our institution started a new initiative for episodically transfused patients with SCD to obtain at least one antibody screen 2-6 months after transfusion as part of their clinical care. A database was created to prospectively track all transfused patients for 1 year and their post-transfusion antibody screen results. Patients received prophylactically CEK-matched RBC units.

RESULTS

During the study year, 138 patients with SCD received a total of 242 RBC transfusions. Patients with a history of an RBC alloantibody (n = 13, 9.4%) had previously received more RBC units than non alloimmunized patients (median 11 vs. 2 RBC units, p = .0002). A total of 337 post-transfusion antibody screens were obtained in 127 patients (92.0%) with 110 patients (79.7%) having at least one antibody screen 2-6 months post-transfusion. With this prospective testing, two new RBC alloantibodies (anti-C and -M) were identified in two patients.

CONCLUSION

It is feasible to test for new RBC alloantibody development in most episodically transfused patients with SCD as part of their routine care. The yield of this screening appears low with CEK matching, but it could still provide important information for individual patients.

Social aspects of chronic transfusions: addressing social determinants of health, health literacy, and quality of life

Chronic monthly transfusions are a lifesaving preventative therapy for many patients with sickle cell disease; however, the burden of this therapy for patients and families is high. In the United States, there is overlap in the population affected by sickle cell disease and those with the greatest burden of social needs. Hematology providers caring for patients with SCD have an opportunity to screen for and mitigate social determinants of health, especially in those receiving chronic transfusion therapy given the frequent interactions with the healthcare system and increased demand on already potentially limited resources. Given the complexity of the treatment and medication regimens, providers caring for patients receiving chronic transfusions should implement universal strategies to minimize the impact of low health literacy, as this therapy imposes a significant demand on the health literacy skills of a family. Despite the social and literacy burden of this intervention, it is reassuring that quality of life is preserved as patients with SCD on chronic transfusion therapy often report higher health related quality of life than their peers receiving other disease modifying therapies.

Prevalence of cardiac abnormalities in sickle cell disease identified using cardiac magnetic resonance imaging

Background

Sickle cell disease (SCD) affects thousands of individuals in the United Kingdom causing significant morbidity and mortality. Modern therapies have been successful in increasing life expectancy, however these patients have an increased risk of cardiovascular complications and the extent to which sickle cell disease affects cardiac function is not well understood. Cardiac magnetic resonance imaging (MRI) is the gold standard imaging modality for evaluating myocardial function. It is known that sickle cell patients can present with pulmonary hypertension, left ventricular diastolic dysfunction, and atrial enlargement however the prevalence of other cardiac abnormalities has not been sufficiently investigated with cardiac MRI. In addition, the European Society of Cardiology (ESC) updated their definition of Heart Failure in 2016 and therefore will need to be re-assessed in this population.

Purpose

To evaluate the prevalence of cardiac abnormalities in the sickle cell population using cardiac MRI and based on the recently updated diagnostic criteria.

Methods

We conducted a retrospective review including all patients with sickle cell disease at a large tertiary hospital in London, United Kingdom who had been referred for cardiac MRI between 2011 and 2019. Data was collected data on various measures of cardiac function including: left ventricular ejection fraction (LVEF), left ventricular hypertrophy, left and right atrial enlargement, regional wall motion abnormalities, valvular disease, myocardial scarring, and cardiac iron load.

Results

82 patients and 123 cardiac MRI scans were reviewed in this study. 68% of patients were female and the average age at time of scan was 37 years. The average left ventricular ejection fraction was 57% (n=82). Cardiac abnormalities were identified in 60% of patients. The most common cardiac abnormalities reported were: valvular regurgitation (46%; n=28), left atrial enlargement (28%; n=19), right atrial enlargement (16%; n=11), left ventricular hypertrophy (11%; n=8), regional wall motion abnormalities (10%; n=7), and myocardial scar with late gadolinium enhancement (9%; n=7). 28% of the patients were diagnosed with Heart Failure; 11% of the patients satisfied the diagnostic criteria for HFpEF (Heart failure with preserved ejection fraction, n=9), 10% with HFrEF (Heart Failure with reduced ejection fraction, n=8), and 7% with HFmrEF (Heart Failure with mid-range ejection fraction, n=6).

Conclusion

Sickle cell disease affects cardiac function in the majority of patients resulting in numerous cardiac abnormalities. We have described the overall extent of these effects using data from cardiac MRI scans, which has not been commonly used thus far. This has implications for both the diagnosis and subsequent management of cardiac abnormalities in this population, and it can be used to further investigate and guide the development of targeted treatments for these patients.

Funding Acknowledgement

Type of funding source: None

Six-month and one-year outcomes with the PASCAL transcatheter valve repair system for patients with mitral regurgitation from the multicentre, prospective CLASP study

Background

Transcatheter mitral valve repair has emerged as a viable option for treating mitral regurgitation (MR). We report results from the multicentre, prospective, single arm CLASP study with the PASCAL transcatheter valve repair system.

Methods

109 patients with clinically significant MR deemed candidates for transcatheter repair by the local heart team were treated in the CLASP study. The study evaluated safety, performance, clinical and echocardiographic outcomes and included an independent clinical events committee and echocardiographic core lab. The primary safety endpoint was a composite MAE rate at 30 days of cardiovascular mortality, stroke, MI, new need for renal replacement therapy, severe bleeding, and re-intervention for study device-related complications.

Results

Mean age was 76 years, 54% male, 57% NYHA Class III/IV, 100% MR grade ≥3+ with 62% functional, 31% degenerative, 7% mixed etiology. Successful implantation was achieved in 95% of patients. At 30 days, the MAE rate was 8.3% including one cardiovascular mortality due to cardiogenic shock as a result of severe bleeding at the contralateral arterial access site for hemodynamic monitoring further complicated by disseminated intravascular coagulation, one stroke, and one conversion to mitral valve replacement surgery. In paired analysis, 88% of patients were in NYHA Class I/II (p&lt;0.001), MR grade was ≤1+ in 79% of patients and ≤2+ in 96% of patients. Significant improvements in 6MWD (+27 m, p&lt;0.001) and KCCQ (+16 points, p&lt;0.001) were observed. The six-month data will be available for presentation. In addition, we report one-year follow up of the first 62 patients (ITT): 93% one-year survival rate (Kaplan-Meier estimate), no stroke, no late reintervention, one late MI. In paired analysis, MR grade was ≤1+ in 82% of patients and ≤2+ in 100% of patients. 88% of patients were in NYHA Class I/II (p&lt;0.001), 6MWD improved by 21 m (p=0.124) and KCCQ improved by 13 points (p&lt;0.001).

Conclusions

This study demonstrates the PASCAL transcatheter valve repair system is safe and resulted in robust MR reduction with 100% of patients achieving MR ≤2+, and ∼ 80% MR ≤1+, sustained at one year. Results show high survival and low complication rates, and sustained improvements in functional status, exercise capacity, and quality of life at one year in patients with clinically significant, symptomatic MR. The CLASP IID/IIF pivotal trial is underway.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Edwards Lifesciences (Irvine, CA)

Geometrical predictors of small virtual neoLVOT size in functional mitral regurgitation

Background

LVOT obstruction is a potentially lethal complication of transcatheter mitral valve replacement (TMVR). An anticipated neoLVOT area of &lt;2cm2 is presumed to imply prohibitive risk. Measurement of the anticipated neoLVOT can be time consuming and requires specialist software to facilitate virtual valve implantation.

Purpose

To determine simple geometrical predictors of prohibitive neoLVOT size.

Methods

165 consecutive, non-calcific FMR patients referred to a transcatheter heart valve program were analysed. Segmentation of the mitral annulus and left heart geometry was performed using CT. Suitability for a default D-shaped TMVR was determined by proprietary annular inclusion criteria. Systolic neoLVOT area was determined via virtual valve implantation of the default TMVR.

Results

Sufficient image data for annular and neoLVOT suitability assessment was available in 152 patients. 105 patients (69%) were suitable for TMVR based on annular measurements. Of these, neoLVOT area was &gt;2cm2 in 88 (84%). Overall, compared to patients not suitable for TMVR (n=64), those suitable had larger ventricles with lower LVEF, and larger annuli (table 1). Using binomial logistic regression involving the variables within table 1, LVESD was the sole statistically significant variable to predict neoLVOT area of &lt;2cm2 (p=0.02). LVESD &lt;48mm had 82% sensitivity and 94% specificity for the presence of prohibitive neoLVOT (figure 1).

Conclusion

Smaller LVESD is a strong predictor of small neoLVOT, and hence LVOT obstruction post default D-shaped TMVR implantation. This simple measure may therefore be used to streamline patient selection for advanced pre-procedural imaging analysis.

Predicting NeoLVOT size &lt;2 cm2

Funding Acknowledgement

Type of funding source: None

First-phase ejection fraction predicts response to cardiac resynchronization therapy and adverse outcomes

Background

Cardiac Resynchronization Therapy (CRT) is an important therapeutic treatment for chronic heart failure. However, even in carefully selected cases up to 40% of patient fail to respond. First-phase ejection fraction (EF1), the ejection fraction up to the time of maximal ventricular contraction, is a novel and more sensitive echocardiographic measure of early systolic function.

Purpose

We examined the value of EF1, to predict response to CRT and clinical outcomes after CRT.

Methods

We analysed echocardiograms from 197 patients who underwent CRT between 2009 and 2018 and were followed to determine clinical outcomes.

Results

Volumetric response rate (reduction in end-systolic volume ≥15%) was 92.3% vs. 12.1%, for those with EF1 in the highest vs. lowest tertiles (p&lt;0.001). A cut-off value of 11.9% for EF1 had &gt;85% sensitivity and specificity for prediction of response to CRT; on multivariate logistic regression analysis incorporating previously defined predictors, EF1 was the strongest predictor of response (OR: 1.563, 95% CI: 1.371–1.782, p&lt;0.001) (table 1). EF1 was also the strongest predictor of a clinical composite score (OR: 1.115, 95% CI: 1.044–1.191, p=0.001). Improvement in EF1 at 6 months after CRT implantation (6.5±5.8% vs 1.8±4.3% in responders vs. non-responders, p&lt;0.001) was the best predictor of heart failure re-hospitalization and death after median follow-up of 29.2 months (HR: 0.819, 95% CI:0.765–0.876, p&lt;0.001).

Conclusion

EF1 is a promising marker to identify patients likely to respond to CRT and most likely provides a measure of myocardial viability that determines response.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation, Wellcome/EPSRC Centre for Medical Engineering

Integrative Review of Lower Extremity Nerve Injury During Vaginal Birth

OBJECTIVE

To describe the incidence, health effects, risk factors, and practice implications of lower extremity nerve injury (LENI) related to vaginal births.

DATA SOURCES

We searched MEDLINE, CINAHL, and PubMed from 2000 to 2020 for peer-reviewed published case reports and research studies of LENI related to vaginal births.

STUDY SELECTION

We identified 188 potential records, and 20 met inclusion criteria (six research studies and 14 case studies).

DATA EXTRACTION

Three independent reviewers extracted details of injuries and births into an Excel spreadsheet and analyzed data using SPSS.

DATA SYNTHESIS

Using birth data from each case study and from four of the six research articles, we found the incidence of LENI in vaginal births was 0.3% to 1.8%. The description of health effects includes affected nerves and the location, description, and duration of symptoms. Analyses of risk factors were limited by missing birth data (length of second stage, birth weight, etc). Vaginal births with LENI were 76% spontaneous, 77% with neuraxial anesthesia, and 64% first vaginal birth. Practice implications focused on prevention through specific positioning strategies. Despite nurses being the primary caregivers during labor, LENI was reported most often in anesthesia journals with virtually no reports in nursing journals.

CONCLUSION

LENI is a potential complication of vaginal birth, and little published research is available on prevention and prognosis. While obstetric and anesthesia factors can cause or contribute to nerve injury, LENI is usually caused by positioning and is considered preventable. Care recommendations include the following: avoid prolonged hyperflexion of women's thighs and knees; minimize time in lithotomy, squatting, or kneeling positions; prevent hand or other deep pressure on lateral knee and posterior thigh areas; avoid motor-blocking neuraxial (epidural) anesthesia; and implement frequent repositioning. The paucity of literature contributes to the lack of awareness of LENI among clinicians.

Estimating insertion length of umbilical arterial and venous catheters in newborn infants: time for change

BACKGROUND

Umbilical catheters are inserted through the umbilical artery or vein at birth and are crucial in neonatal care. There are several different methods of estimating adequate insertion length of umbilical catheters based on one of two hypotheses; that the insertion length of the UC is correlated to either the infant's birth weight or an external length measurement.

AIM

To review the published literature on methods of estimating insertion lengths of umbilical arterial catheters (UACs) and umbilical venous catheters (UVCs) in newborn infants.

METHODS

Systematic search on Medline was undertaken using keywords for relevant papers up to March 2019. Papers were selected by manual search of titles and abstracts.

RESULTS

Formulae for predicting umbilical catheter insertion length are unreliable, particularly for UVCs. There is also conflicting evidence around whether birth weight-based formulae are more reliable than external length-based formulae. Studies comparing various methods to determine their efficacy to show that current formulae have a low accuracy for determining both UVC and UAC positioning.

CONCLUSIONS

Current formulae for estimating insertion length of umbilical catheters are not fit for purpose. We propose a new observational study which uses a new external length measurement, the sternal notch to umbilicus length, to develop a more reliable formula for the insertion of UVC and UAC to an adequate length.

Search for Axionlike Particles Produced in e^{+}e^{-} Collisions at Belle II

We present a search for the direct production of a light pseudoscalar a decaying into two photons with the Belle II detector at the SuperKEKB collider. We search for the process e^{+}e^{-}→γa, a→γγ in the mass range 0.2<m_{a}<9.7  GeV/c^{2} using data corresponding to an integrated luminosity of (445±3)  pb^{-1}. Light pseudoscalars interacting predominantly with standard model gauge bosons (so-called axionlike particles or ALPs) are frequently postulated in extensions of the standard model. We find no evidence for ALPs and set 95% confidence level upper limits on the coupling strength g_{aγγ} of ALPs to photons at the level of 10^{-3}  GeV^{-1}. The limits are the most restrictive to date for 0.2<m_{a}<1  GeV/c^{2}.

Postmastectomy Radiation Therapy Planning After Immediate Implant-based Reconstruction Using the European Society for Radiotherapy and Oncology-Advisory Committee in Radiation Oncology Practice Consensus Guidelines for Target Volume Delineation

AIMS

To evaluate how common radiation therapy techniques perform in the setting of the new European Society for Radiotherapy and Oncology-Advisory Committee in Radiation Oncology Practice (ESTRO-ACROP) delineation recommendations for immediate breast reconstruction (IBR).

MATERIALS AND METHODS

Seven Danish radiation therapy centres and six international European centres participated in this project. Two breast cancer cases (one left-sided and one right-sided) with a retropectoral implant were chosen for radiation therapy planning using deep-inspiration breath-hold. Target volumes were delineated according to ESTRO-ACROP delineation recommendations. The centres were asked to plan the cases using any radiation therapy technique according to the Danish Breast Cancer Group plan objectives.

RESULTS

In total, 35 treatment plans were collected. Half of the submitted plans, for both the left-sided and the right-sided case, used the field-in-field (FiF) technique (nine for each), a quarter used volumetric arc radiation therapy (VMAT; five for right-sided, four for left-sided) and the remaining quarter was a mix of inverse intensity-modulated radiation therapy (IMRT), helicoidal therapy and hybrid (combined open fields and VMAT) techniques. Mean clinical target volume doses were in the range 99-102% of the prescribed dose. The median FiF mean heart dose (MHD) for right-sided radiation therapy was 1 Gy (range 0.8-3.7) and 5.2 Gy for left-sided radiation therapy (range 2.2-6.5). For right-sided radiation therapy, the median VMAT MHD was 3.42 Gy, for IMRT was 2.3 Gy and for helicoidal therapy was 5.1 Gy. For left-sided radiation therapy, the median VMAT MHD was 6.3 Gy, for IMRT was 7.8 Gy and for helicoidal therapy was 7.3 Gy.

CONCLUSIONS

Different radiation therapy techniques could be used to plan radiation therapy in the setting of IBR. FiF provided good coverage with acceptable organ at risk doses. The best dose distribution results as a trade-off between the objectives of target volume coverage and high-dose organ at risk inclusion. The radiation therapy technique affects the interplay between these objectives.

Investigating alternative materials to EPDM for automatic taps in the context of Pseudomonas aeruginosa and biofilm control

BACKGROUND

Automatic taps use solenoid valves (SVs) which incorporate a rubber (typically EPDM) diaphragm to control water flow. Contaminated SVs can be reservoirs of opportunistic pathogens such as Pseudomonas aeruginosa; an important cause of healthcare-associated infection.

AIMS

To investigate the attachment and biofilm formation of P. aeruginosa on EPDM and relevant alternative rubbers to assess the impact on water hygiene in a laboratory model.

METHODS

Biofilm formation on EPDM, silicone and nitrile rubber coupons was investigated using a CDC biofilm reactor. SVs incorporating EPDM or nitrile rubber diaphragms were installed on to an experimental water distribution system (EWDS) and inoculated with P. aeruginosa. P. aeruginosa water levels were monitored for 12-weeks. SVs incorporating diaphragms (EPDM, silicone or silver ion-impregnated silicone rubber), pre-colonized with P. aeruginosa, were installed and the effect of flushing as a control measure was investigated. The concentration of P. aeruginosa in the water was assessed by culture and biofilm assessed by culture and microscopy.

FINDINGS

Bacterial attachment was significantly higher on nitrile (6.2 × 10⁵ cfu/coupon) and silicone (5.4 × 10⁵ cfu/coupon) rubber than on EPDM (2.9 ×10⁵ cfu/coupon) (P<0.05, N = 17). Results obtained in vitro did not translate to the EWDS where, after 12-weeks in situ, there was no significant difference in P. aeruginosa water levels or biofilm levels. Flushing caused a superficial reduction in bacterial counts after <5 min of stagnation.

CONCLUSION

This study did not provide evidence to support replacement of EPDM with (currently available) alternative rubbers and indicated the first sample of water dispensed from a tap should be avoided for use in healthcare settings.

Red cell exchange for patients with sickle cell disease: an international survey of current practices

INTRODUCTION

Red cell exchange (RCE) therapy is increasingly used to treat patients with acute or chronic manifestations of sickle cell disease (SCD). However, little is known regarding the most safe and effective practice parameters associated with this particular therapy.

METHODS

A SCD subcommittee of members of the American Society for Apheresis (ASFA) developed a 122-question survey and administered it via email to other ASFA members. The survey inquired about clinical indications for treatment, practice patterns, and transfusion policies for RCE when used for patients with SCD.

RESULTS

Ninety-nine distinct institutions completed the survey. Twenty-one (21%) were from outside of the US. Twenty-two (22%) provided chronic transfusion therapy to >10 patients, and both adult (25%) and pediatric-focused services (20%) were represented. Common acute indications for RCE included acute chest syndrome, acute ischemic stroke, and pre-surgical prophylaxis. Common chronic indications included primary stroke prophylaxis, secondary stroke prophylaxis, and recurrent acute chest syndrome. Respondents most commonly set a post-RCE treatment target of 30% for the hematocrit and hemoglobin S levels, regardless of the therapeutic indication. Units for RCE were phenotypically matched in 95% of cases. About 40% of respondents reported using isovolemic hemodilution.

CONCLUSIONS

This survey solicited the current practice variations in RCE from a diverse range of practice sites. Many sites reported similar practice patterns and challenges but some variations emerged. To our knowledge, this survey represents the largest and most in-depth investigation of the use of RCE for patients with SCD, and could inform future studies in the field.

Search for an Invisibly Decaying Z^{'} Boson at Belle II in e^{+}e^{-}→μ^{+}μ^{-}(e^{±}μ^{∓}) Plus Missing Energy Final States

Theories beyond the standard model often predict the existence of an additional neutral boson, the Z^{'}. Using data collected by the Belle II experiment during 2018 at the SuperKEKB collider, we perform the first searches for the invisible decay of a Z^{'} in the process e^{+}e^{-}→μ^{+}μ^{-}Z^{'} and of a lepton-flavor-violating Z^{'} in e^{+}e^{-}→e^{±}μ^{∓}Z^{'}. We do not find any excess of events and set 90% credibility level upper limits on the cross sections of these processes. We translate the former, in the framework of an L_{μ}-L_{τ} theory, into upper limits on the Z^{'} coupling constant at the level of 5×10^{-2}-1 for M_{Z^{'}}≤6  GeV/c^{2}.

Salmonella and Shiga Toxin-Producing Escherichia coli in Products Sampled in the Food Safety and Inspection Service Raw Pork Baseline Study

The Food Safety and Inspection Service (FSIS) conducts microbiological baseline studies to determine national prevalence of select foodborne pathogens in federally inspected meat and poultry products and to obtain data for risk assessments. The FSIS conducted a baseline study from 1 June 2017 through 31 May 2018 to characterize and determine the prevalence of Salmonella and assess the occurrence of Shiga toxin-producing Escherichia coli (STEC) in a variety of raw pork products. In total, 4,014 samples from slaughter and processing establishments were analyzed for Salmonella; a subset of these samples (1,395) from slaughter establishments were also analyzed for STEC. Analyses determined that the national prevalence of Salmonella in raw pork products was highest in comminuted products (28.9%), followed by intact cuts (5.3%) and nonintact cuts (3.9%). Less than 1% of samples analyzed were positive for the top seven STEC. Our findings indicate there is a need for additional pathogen reduction strategies for raw pork products.

Transformation of Chlorofluorocarbons Investigated via Stable Carbon Compound-Specific Isotope Analysis

Compound-specific isotope analysis (CSIA) is a valuable tool in contaminant remediation studies. Chlorofluorocarbons (CFCs) are ozone-depleting substances previously thought to be persistent in groundwater under most geochemical conditions but more recently have been found to (bio)transform in some laboratory experiments. To date, limited applications of CSIA to CFCs have been undertaken. Here, biotransformation-associated carbon isotope enrichment factors, ε_C,bulk for CFC-113 (ε_C,bulk = -8.5 ± 0.4‰) and CFC-11 (ε_C,bulk = -14.5 ± 1.9‰), were determined. δ¹³C signatures of pure-phase CFCs and hydrochlorofluorocarbons were measured to establish source signatures. These findings were applied to investigate potential in situ CFC transformation in groundwater at a field site, where carbon isotope fractionation of CFC-11 suggests naturally occurring biotransformation by indigenous microorganisms. The maximum extent of CFC-11 transformation is estimated to be up to 86% by an approximate calculation using the Rayleigh concept. CFC-113 δ¹³C values in contrast were not resolvably different from pure-phase sources measured to date, demonstrating that CSIA can aid in identifying which compounds may, or may not, be undergoing reactive processes at field sites. Science and public attention remains focused on CFCs, as unexplained source inputs to the atmosphere have been recently reported, and the potential for CFC biotransformation in surface and groundwaters remains unclear. This study proposes δ¹³C CSIA as a novel application to study the fate of CFCs in groundwater.

Comparison of Kjeldahl Method for Determination of Crude Protein in Cereal Grains and Oilseeds with Generic Combustion Method: Collaborative Study

Seven laboratories participated in a collaborative study to extend the applicability of the AOAC generic combustion method for determination of crude protein in animal feed (990.03) to include determination in cereal grains and oilseeds. In the study, method 990.03 was compared with the AOAC mercury catalyst Kjeldahl method for determination of protein in grains (979.09) and crude protein in animal feed (954.01). The study also evaluated the effect on the results of fineness of grind. For determination of crude protein in grains and oilseeds by the combustion method, standard deviations for repeatability and reproducibility ranged from 0.10 to 0.37 and from 0.25 to 0.54, respectively, and relative standard deviations for repeatability and reproducibility ranged from 0.77 to 2.57% and from 1.24 to 3.15%, respectively. The combustion method was adopted first action by AOAC International for determination of crude protein in cereal grains and oilseeds containing 0.2- 20% nitrogen.

563 Early systolic function is impaired in patients with heart failure and preserved ejection fraction and is a more important predictor of clinical outcomes than diastolic function

Funding Acknowledgements

British Heart Foundation

Aims

First-phase ejection fraction (EF1), the ejection fraction up to the time of maximal ventricular contraction may be impaired in heart failure with preserved ejection fraction (HFpEF), with homeostatic mechanisms preserving the overall ejection fraction. We examined whether EF1 is impaired and whether it predicts adverse outcomes in patients with HFpEF.

Methods and Results

We examined EF1 in patients with HFpEF diagnosed according to European Society of Cardiology guidelines, in subjects with pre-clinical diastolic dysfunction and in control subjects with no evidence of heart failure. The predictive value of EF1 for a combined end-point of re-hospitalisation for heart failure and death from any cause was compared to that of conventional echocardiographic and other indices. There was a progressive impairment of EF1 in patients with diastolic dysfunction and HFpEF compared to those without evidence of heart failure (P &lt; 0.001). In 180 HFpEF patients followed for a median of 14.7 months, 101 patients reached the primary endpoint (61 deaths and 40 hospitalisations). EF1 was the most powerful predictor of events (table 1). A cut-off value of 19.4% gave hazard ratios (for EF1 &lt; 19.4% compared to ≥19.4%) of 3.04 (figure 1), (95% confidence interval 2.014 – 4.604, P &lt; 0.001) unadjusted, and 2.976 (1.887 – 4.695, P &lt; 0.001) adjusted for age, gender, other echocardiographic indices (including EF, E/e’ ratio, stroke volume and left atrial volume index) and N-terminal pro-brain natriuretic peptide.

Conclusion

Early systolic function is impaired in HFpEF and is a powerful predictor of clinical outcomes. Therapies targeted at improving early systolic function may improve outcomes in HFpEF.

Table 1 HR CI (95%) P value Age 1.020 1.001 - 1.039 0.042 Female Gender 1.989 1.254 - 3.156 0.003 ln NT-proBNP 1.354 1.096 - 1.672 0.005 Haemoglobin 0.992 0.980 - 1.005 0.225 eGFR 0.997 0.988 - 1.006 0.568 Structural Heart Disease 0.748 0.439 - 1.274 0.285 Diastolic Dysfunction 0.694 0.445 - 1.082 0.107 Ejection Fraction 1.031 0.996 - 1.068 0.082 Stroke Volume index 0.963 0.940 - 0.986 0.002 TPAVF 0.995 0.980 - 1.005 0.230 EF1 0.900 0.869 - 0.932 &lt;0.001 Multivariate analysis of predictors of events

Abstract 563 Figure 1 Kaplan-Meier Curve